Many metallurgical vessels have tap holes for removing a portion of a molten bath contained within the vessel. The tap holes often operate at a lower temperature than the molten bath in the vessel itself, even if the tap holes are preheated. As a result, the molten bath discharged through the tap holes can solidify, thereby preventing further discharge of the molten bath.
Tap holes can be opened for tapping, for example, by applying oxygen jets to heat or mechanical drilling or both to free up a previously blocked tap hole. However, controlling the tapping can be difficult and dangerous once the tap holes are open. Typically, flow only ceases once the level of the molten bath in the furnace reaches a point at or below the tap hole inlet. However, the amount of molten material removed in this manner is dependent on the location of the tap hole. Limiting the amount of melt removed in this manner can cause escape of noxious fumes from the reactor into the surrounding atmosphere.
Therefore, a need exists for a new apparatus and method for controlling tapping of a molten bath to eliminate or minimize the problems described above.